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Several viral, bacterial, and parasitic diseases have been associated with cognitive function and neuropsychiatric outcomes in humans, including human T-cell lymphotropic virus 1 (HTLV-1). In this study, we sought to further generalize previously reported associations of cognitive function and depression with HTLV-1 seropositivity and serointensity using a community-based sample of adults aged approximately 40 to 70 years (mean = 55.3 years) from the United Kingdom. In this sample, the results of adjusted linear regression models showed no associations of HTLV-1 seropositivity or serointensity with reasoning, pairs-matching, or reaction-time cognitive tasks or with depression. In addition, neither age, sex, educational attainment, nor income moderated associations of HTLV-1 seropositivity or serointensity with cognitive function or depression. In this middle-aged to older middle-aged adult community sample, HTLV-1 seropositivity and serointensity do not appear to be associated with reasoning, pairs-matching, and reaction-time tasks or with depression.

Plant colonization of islands may be limited by the availability of symbionts, particularly arbuscular mycorrhizal (AM) fungi, which have limited dispersal ability compared to ectomycorrhizal and ericoid (EEM) as well as orchid mycorrhizal (ORC) fungi. We tested for such differential island colonization within contemporary angiosperm floras worldwide. We found evidence that AM plants experience a stronger mycorrhizal filter than other mycorrhizal or non-mycorrhizal (NM) plant species, with decreased proportions of native AM plant species on islands relative to mainlands. This effect intensified with island isolation, particularly for non-endemic plant species. The proportion of endemic AM plant species increased with island isolation, consistent with diversification filling niches left open by the mycorrhizal filter. We further found evidence of humans overcoming the initial mycorrhizal filter. Naturalized floras showed higher proportions of AM plant species than native floras, a pattern that increased with increasing isolation and land-use intensity. This work provides evidence that mycorrhizal fungal symbionts shape plant colonization of islands and subsequent diversification.

Infecting much of the world's population, the herpesviridae virus cytomegalovirus has been associated with lower cognitive function in some but not all studies. In this study, we further investigate associations between cytomegalovirus and cognitive function in a community-based sample of adults aged 40 to 70 years (M = 55.3; SD = 8.1) from the United Kingdom. Adjusted multiple-regression modeling showed no significant associations between cytomegalovirus and performance on nine cognitive tasks. Further, in adjusted interaction models, age, sex, educational attainment, and income did not moderate associations between cytomegalovirus and cognitive function. In this community-based adult sample, cytomegalovirus was not associated with cognitive function.

Infecting approximately one-third of the world’s human population, Toxoplasma gondii has been associated with cognitive function. Here, we sought to further characterize the association between Toxoplasma gondii and cognitive function in a community sample of adults aged approximately 40 to70 years. Using adjusted linear regression models, we found associations of Toxoplasma gondii seropositivity with worse reasoning (b = -.192, p < .05) and matrix pattern completion (b = -.681, p < .01), of higher anti-Toxoplasma gondii p22 antibody levels with worse reasoning (b = -.078, p < .01) and slower Trails (numeric) performance (b = 5.962, p < .05), of higher anti-Toxoplasma gondii sag1 levels with worse reasoning (b = -.081, p < .05) and worse matrix pattern completion (b = -.217, p < .05), and of higher mean of the anti-Toxoplasma gondii p22 and sag1 levels with worse reasoning (b = -.112, p < .05), slower Trails (numeric) performance (b = 9.195, p < .05), and worse matrix pattern completion (b = -.245, p < .05). Neither age nor educational attainment moderated associations between the measures of Toxoplasma gondii seropositivity or serointensity. Sex, however, moderated the association between the sag1 titer and digit-symbol substitution and the association between the mean of the p22 and sag1 levels and digit-symbol substitution, and income moderated the association between Toxoplasma gondii seropositivity and numeric memory and the association between the p22 level and symbol-digit substitution. Based on the available neuropsychological tasks in this study, Toxoplasma gondii seropositivity and serointensity were associated with some aspects of poorer executive function in adults., Author summary Toxoplasma gondii is a parasite that reproduces in cats but that can infect other animals and humans. Toxoplasma gondii has an affinity for the brain and infection results in a long-term immune response that may have negative effects. Animal models have shown that Toxoplasma gondii can affect behavior and cognition (thinking). In humans, the association is less clear, but there are associations between infection and variety of psychiatric and neurological conditions such as schizophrenia and epilepsy. Toxoplasma gondii may even increase the risk of dementia. If true, it is possible that the presence of this infection may affect thinking long before the onset of dementia. We sought to determine if the presence of antibodies in the blood to Toxoplasma gondii, which is the immune system’s response to past infections, might be associated with performance on measures of cognition. We analyzed a large dataset, the UK Biobank, which includes measures of cognition and blood test results for antibodies to Toxoplasma gondii. We found that both the presence of antibodies as well as the amount of these antibodies were related to some aspects of cognition, particularly problem solving and reasoning in otherwise healthy adults ages 40 to 69 years.

Objective Insomnia is associated with suicidality, although the mechanisms of this association are unclear. This study sought to replicate previous findings showing that insomnia symptoms but not sleep duration are associated with frequency of suicidal ideation in adults. We further investigated whether depression or sleep duration moderates the association between insomnia symptoms and frequency of suicidal ideation. Materials and Methods We used the 2005–2006 cycle of the National Health and Nutrition Examination Survey to replicate previously reported findings from the 2007–2008 cycle. We used ordered logistic regression to determine whether insomnia symptoms were associated with frequency of suicidal ideation independently of depression and other potential confounds. To extend these findings, we tested whether depression or sleep duration moderated the association between insomnia symptoms and frequency of suicidal ideation. We further replicated these findings in parallel analyses using the combined data from the 2005–2006 and 2007–2008 cycles. Results This study replicated previous results showing that insomnia symptoms are associated with frequency of suicidal ideation in the NHANES 2005–2006 cycle (OR = 1.09, p < 0.05), even after adjusting for potentially confounding variables, including depression. Neither depression nor sleep duration moderated this association. Difficulty with sleep maintenance insomnia symptoms were most robustly associated with frequency of suicidal ideation (OR ≥ 1.97, p < 0.05). Sleep duration was not robustly associated with suicidal ideation. Conclusions In this study, we found that insomnia symptoms were uniquely associated with frequency of suicidal ideation. This association cannot be explained by the shared association with depression or sleep duration.

Purpose The purpose of this paper is to review some of the causes of secondary headache particularly focusing on the subcategories of secondary headache in the International Classification of Headache Disorders, 3rd edition, the clinical features of these headaches, and their associated features and management. Overview Headache attributed to trauma or injury to the head and/or neck, headache attributed to cranial or cervical vascular disorder, headache attributed to non-vascular intracranial disorder, headache attributed to a substance or its withdrawal, headache attributed to infection, headache attributed to disorder of homeostasis, and headache or facial pain attributed to disorder of the cranium, neck, eye, ears, nose, sinuses, teeth, mouth, or other facial or cervical structure are discussed in this paper. Discussion Headache is a common symptom of multiple medical conditions. Although a minority of headache patients have a secondary basis for their headaches, it is important to identify clinical features of secondary headache disorders including both the headache and non-headache features of the condition, diagnose the secondary etiology correctly, and treat them appropriately.

Objective: We investigated two hypotheses: First, incident CHD, defined as myocardial infarction or definite angina, leads to faster long-term cognitive decline. Second, among those with CHD, treatment with CABG surgery or PCI leads to slower long-term cognitive decline. Methods: The Cardiovascular Health Study is a cohort of US adults aged 65+. Global cognitive ability was assessed annually up to 9 times from 1990 to 1998 with the 100-point Modified Mini-Mental State Examination (3MS). We estimated trajectories of 3MS scores in the absence of stroke, adjusting for demographics, health behaviors, and comorbidities. For hypothesis 1, we compared 3MS trajectory after incident CHD with 3MS trajectory in the absence of CHD, censoring at first receipt of CABG/PCI. For hypothesis 2, among participants with CHD, we compared 3MS trajectory after first receipt of CABG/PCI with 3MS trajectory without CABG/PCI. Results: For hypothesis 1, of 4,122 participants, 398 had incident CHD during a mean of 5.9 years of follow-up. Figure Panel A shows model-predicted mean 3MS trajectories without CHD (blue) and after incident CHD (red) diagnosed at ages 70, 75, 80, or 85. Model-predicted 3MS score declined faster after incident CHD, especially for CHD diagnosed at age 80 or later. For example, after incident CHD at age 85, predicted 5-year decline in mean 3MS score through age 90 was 13.9 points (95% CI: 11.0, 16.7) versus 8.9 points (95% CI: 8.1, 9.7) among those without CHD. For hypothesis 2, of 1,183 participants who had prevalent or incident CHD, 118 had their first CABG/PCI during a mean of 4.1 years of follow-up. Model-predicted 3MS score declined faster after first receipt of CABG/PCI ( Figure Panel B ). Conclusions: Older adults diagnosed with incident CHD had faster average cognitive decline than those without CHD. However, treatment with CABG/PCI did not slow cognitive decline among those with CHD. This finding may be due to adverse effects of CABG/PCI on brain health or CABG/PCI recipients having more severe CHD or more cerebral atherosclerosis.